It takes a long time and a lot of tests to find out if you have Dermatomyositis. I was diagnosed about a year & 1/2 ago, but I've had symptoms for at least two years. Dermatomyositis is easier to diagnos than Polymyositis because of the rash. You should be seeing a Rheumatologist for this disease. I started treatment with Prednisone (sterioid)at 5mg a day which worked for about six months. I had a flare up and went to 10 mg a day but that didn't help. I am now on 10mg/day Prednisone and I am taking Methotrexate (3x/day one day a week) and feeling much better (80%). Good luck!